one of the down falls of the jury system is that they do precisely what philosophers like Jeremy Bentham tried to undo in England - sentencing based on emotion rather than reason, and based on conventions of what behavior is more offensive than other rather than what behavior is more harmful than another. For example, homosexuality was considered more offensive than murder, even though consensual sex between two adults didn't seem to unfairly take advantage of anyone, and was given a stricter sentence. This is why the doctors in US are near ready to quit - juries return absurdly high verdicts.

Juries are allowed to have certain biases but not others (for example, they can't be part of the family or friends network of one of the parties). Ideally, the system is supposed to provide the parties with an unbiased jury, but that rarely happens. I wonder if it truly is inappropriate for a verdict to be tossed out if it shows a substantial bias - thereby inhibiting reason - by the consulting the Bible thing they did. More details are necessary for this - if the Bible consultation was for personal reference, but the verdict was a result of a debate based on reason and the laws and the jury instructions, then there is no reason to toss out the verdict, but if the verdict was a result of the stuff found in the Bible, then the verdict is based on laws different from the laws of the country, and therefore ought to be tossed out.